4 or 3 size hose for Brakes??

[supercub]

I've done some researching and haven't found much yet. I've looked at a couple of Cubs and one has -3 and the other has -4 size hose. Called Univair and they're using -4 hose, so I'm assuming that's the correct size. Just wondering what you're using.

[mike mcs repair]

-4 is original as far as I can remember....


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[bob turner]

Original was automotive. #4 inverted flare and 1/8" pipe. We have not yet figured out which Plymouth the original flex hoses came off of, but current production hoses are 4000 psi operating, 5000 psi burst, and require a #3 inverted flare to 1/8" pipe to fit most Scott brake bells. Eleven bucks each.

[supercub]

Thanks for the info, 4 is what I remembered too, but then I saw -3 on a Cub. I suppose it's not to critical, since it's pressure not necessarily volumne for brakes. Thanks again.

[RaisedByWolves]

-4

https://www.summitracing.com/parts/AER-FBM1101


https://www.summitracing.com/parts/AER-FCC0410


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[AkPA/18]

Not saying it is right but I used - 3. I used it because it was easier to work with and easier to make up clamps for the gear legs. On a side note Whip amphibs use - 3 for brakes and -4 for the retract gear.

[bob turner]

I think once you deviate from the original you can use anything you want. I am pretty careful to specify what hoses and fittings I use on field approved brake systems. For Cubs and Aeroncas I always use the equivalent of original equipment, and I get them approved in block 3.

Interesting story - the STC disc brakes for J3s use copper tubing. The reason is that copper was original, so no FAA hassle. Aluminum tubing would have required engineering approval beyond that required for the calipers, discs, etc.

I don't know what the factory used in the 1970s, but during the 8:00x4 era it was all auto stuff. You go to Aeroquip, presumably, as a minor alteration. Remember, Aeroquip is 600 psi stuff, and auto is 4000 psi.

I better say - opinion. I really caught it for my lousy advice last week - not here - I think a fellow forumite turned me in, or got a contract on me . . .

[supercub]

Thanks for the feedback, here's another question, this one about fuel hose size. The Continental O-200 that I bought came with a -5 hose size from the gascolator to the carb. My friends Cub with a O-200 has a -6 hose. Any idea which one is correct?

[wireweinie]

Look in the parts manual. Everything in there is 'blessed off' as legal/correct. It's an airframe item by the way.

Web

[supercub]

I did check the parts manual, but I was looking at the engine area, just dawned on me to look at the fuel section duhh !! LOL. Doesn't say what size hose, but did find some fittings, and they're -6, Thanks

Look in the parts manual. Everything in there is 'blessed off' as legal/correct. It's an airframe item by the way.

Web

[jbc]

The guy who owns Pegasus racing (https://www.pegasusautoracing.com/) is an RV builder and in the distant past he posted on the Van's Air Force website that -3 hoses were used on 3000 lb, race cars so they ought to be OK for RVs. Made sense to me and I followed his advice. No problems after 2 airplanes, and using -3 on a the 3rd. Plus his website sells prefabricated stainless steel wire braided brake lines is an variety of lengths at very reasonable rates.

John Ciolino
Bearhawk patrol

[C-FIJK]

Where do you get the tool to make the hose and fittings up with ?

-4

https://www.summitracing.com/parts/AER-FBM1101


https://www.summitracing.com/parts/AER-FCC0410


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[AkPA/18]

Gerry,
I use a dremel with a cutoff wheel to cut the braid carefully without disturbing the inner teflon.I use a razor knife to cut the teflon tube for a clean cut.I use a small awl to open the braid to expose the teflon tube to slide the brass olive or ferrel over the tube. Then just fit the assembly together and tighten with wrenches. The most critical part is making sure the olive is fully seated on the teflon tube.Sometimes if it is a tight frustrating fit I will lightly open the taper of the olive with a larger center punch. If anyone else has a technique they like I would love to hear it.

[bob turner]

Good idea with the Dremel. I just borrow a mandrel.

[AkPA/18]

Bob
I don't see how to use a mandrel for these reusable ptfe hose fittings. There are also YouTube videos out there.They are different from other aeroquip hoses.This is also the setup that wip uses on their amphibs.Not positive but I believe these aeroquip hoses are 3000 psi

[bob turner]

You are correct. I am only familiar with Aeroquip. I rarely build these things up. I use them only for engine oil applications - oil pressure gauge, oil cooler, etc.

[AkPA/18]

These are Aeroquip just different than what you are used to.